Display screen or portion therefof with a graphical user interface



The FIGURE is a front view of a display screen or portion thereof with agraphical user interface showing our new design.

The outermost broken lines in the FIGURE represent the display screen orportion thereof that forms no part of the claimed design. The remainingbroken lines show portions of the graphical user interface that form nopart of the claimed design.

CLAIM We claim the ornamental design for a display screen or portionthereof with a graphical user interface, as shown and described.